JP2017043867A - Sheet-like material and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet-like material in which the exposure of woven fabric-forming multifilaments present in a surface is inhibited, and which is suitable for artificial leather excellent in surface uniformity, high in strength, and rich in flexibility; and to provide a method for producing the same.SOLUTION: A sheet-like material is formed by entanglement of ultrafine fibers with a woven fabric and is subjected to napping. In the sheet-like material, the number of woven fabric-forming yarns exposed to the surface of a napped surface formed is 1/400 cmor less. In a method for manufacturing the sheet-like material, when the ultrafine fibers are entangled and integrated with the woven fabric by needle punching to obtain the sheet-like material, entanglement by needle punching is performed under a condition satisfying the following requirement, and the sheet-like material is subjected to napping. 0.22≤S1/S2≤0.28, S1: the area (mm) of the largest inscribed circle within a grid in the smallest pattern of weaving, S2: the cross-section area (mm) of a needle blade part in contact with the woven fabric.SELECTED DRAWING: None

Description

  The present invention relates to a sheet-like material suitable for artificial leather having good surface quality and excellent wear characteristics, and a method for producing the same.

  Conventionally, artificial leather is generally made by adding a polymer elastic body to a nonwoven fabric made of ultrafine fibers in order to obtain flexibility and mechanical performance similar to natural leather. Various methods for producing artificial leather have been proposed so far.

  For example, when artificial leather is used for a skin material such as a car seat or a chair, the sheet-like material constituting the artificial leather may be distorted due to repeated use over a long period of time. A method has been proposed in which a woven or knitted fabric is entangled and integrated into an artificial leather having high strength, low elongation and high flexibility (Reference Document 1).

  According to this proposed method, it is described that an artificial leather having good mechanical properties can be obtained. However, when a woven and knitted fabric and a nonwoven fabric are entangled and integrated by a needle punch, the woven or knitted fabric is formed by a needle. Due to damage, the mechanical properties inherent to the woven or knitted fabric cannot be fully utilized, and the end of the multifilament that forms the woven or knitted fabric cut by the needle punch is exposed on the nonwoven fabric surface, thereby improving the uniformity of the nonwoven fabric surface. May be significantly reduced. Further, if the knitted fabric is densified and the strength is compensated for in anticipation of this damage, there is a problem that the rigidity of the woven / knitted fabric is increased, which is disadvantageous for the purpose of obtaining a lightweight and flexible artificial leather.

  Therefore, as a method for improving the mechanical properties of woven and knitted fabrics, woven and knitted fabrics are composed of high-strength fibers such as high-strength polyvinyl alcohol-based synthetic fibers (high-strength vinylon fibers) and wholly aromatic polyamide (aramid) fibers. An artificial leather base that is intertwined with a nonwoven fabric has been proposed (see Patent Document 2).

  However, even in the case of this proposal, if the notch at the tip of the needle is caught in the knitted fabric during needle punching, not only will the multifilaments constituting the knitted fabric be damaged, but also the wear of the needle Will be abruptly advanced, and it will not be possible to stably process long sheets.

  In addition, as a method of minimizing damage to the woven or knitted fabric from the needle during needle punching, the relationship between the diameter of the multifilaments constituting the woven or knitted fabric and the throat depth of the needle used in the needle punch is clearly shown. A manufacturing method for suppressing damage to the yarn constituting the knitted fabric (see Reference 3), the weft density of the multifilament constituting the knitted fabric and the diameter of the needle used for the needle punch, and the knitted fabric A manufacturing method (see Reference 4) that suppresses damage to the multifilaments that are formed has been proposed.

  When the above manufacturing method is used, strength reduction can be prevented without the needle being caught by the fibers constituting the knitted or knitted fabric. However, in these proposals, when needle breakage that occurs regularly in the needle punch occurs. It is not mentioned at all, and it is difficult to say that the method can be manufactured stably.

JP-A-62-78281 JP-A-2005-240197 Japanese Patent Publication No. 7-13344 JP 2007-270379 A

  Therefore, an object of the present invention is to suppress the exposure of multifilaments constituting the fabric on the surface, and is excellent in surface uniformity and sheet-like material suitable for high-strength and flexible artificial leather, and a method for producing the same Is to provide.

The present invention is intended to solve the above-mentioned problems, and the sheet-like material of the present invention is such that the fine fibers and the fabric are intertwined, and the yarn constituting the fabric exposed on the surface is 1 piece / 400 cm ² or less. It is a sheet-like material characterized by being.

According to a preferred aspect of the sheet-like material of the present invention, the sheet-like material has a raised surface formed by a raised process, and the number of yarns constituting the fabric exposed on the surface of the raised surface is 1/400 cm ^2. It is as follows.

  According to a preferred embodiment of the sheet material of the present invention, the sheet material is impregnated with a polymer elastic body.

The manufacturing method of the sheet-like material of the present invention satisfies the following conditions in the manufacturing process of the sheet-like material in which ultrafine fibers and a woven fabric are entangled with a needle punch.
0.22 ≦ S1 / S2 ≦ 0.28
S1: Maximum inscribed circle area in the lattice in the minimum weave pattern (mm ² )
S2: Cross-sectional area of the needle blade part in contact with the fabric (mm ² )
According to the preferable aspect of the manufacturing method of the sheet-like material of this invention, it is that a napping process is performed and a napped surface is formed in the surface.

According to the present invention, in a sheet-like material in which a nonwoven fabric and a woven fabric are entangled and integrated with a needle punch, damage to the multifilaments constituting the woven fabric can be suppressed. .0 pieces / 400 cm can be suppressed to ² or less, the sheet-like product increased dense fabric in anticipation of strength reduction due to damage of the multi-filament rich in unnecessary and flexibility that make up the fabric, i.e., excellent in high strength and surface uniformity In addition, a sheet-like material that can provide a leather-like material that is lightweight and rich in flexibility is obtained. The sheet-like product of the present invention is suitable as a suede-like artificial leather or a silver-like artificial leather for interior use, particularly for car seats, chairs and sofa skin materials.

  In the sheet-like material obtained by entanglement and integration of a woven fabric inside or on one side of a non-woven fabric composed of ultrafine fibers, the present inventors have intensively studied to provide high flexibility and form stability together, and solutions Got. The details will be described below.

The sheet-like material of the present invention is a sheet-like material in which the ultrafine fibers and the fabric are intertwined, and the number of yarns constituting the fabric exposed on the surface is 1/400 cm ² or less.

  First, the fabric used in the present invention will be described.

  In the case of a woven fabric used in the sheet-like material of the present invention, a plain structure is preferably used as a basic structure. Twill and satin can be used as the woven structure of the woven fabric, but because the structure has anisotropy, the behavior is different with respect to the external force in the oblique direction, and misalignment tends to occur if the woven fabric density is low for handling, A plain fabric is preferably used.

  As the fibers constituting the woven fabric, synthetic fibers such as polyester, polyamide and aramid are preferably used. For these fiber types, it is a more preferable aspect from the viewpoint of dyeing fastness to use the same material as the fiber constituting the nonwoven fabric. Of course, any fiber that can be knitted can be used, such as, but not limited to, natural fibers such as cotton, wool and silk, regenerated fibers such as rayon, and semi-synthetic fibers such as acetate. High-strength fibers typified by high-strength polyvinyl alcohol-based synthetic fibers (high-strength vinylon fibers) and wholly aromatic polyamide (aramid) fibers can also be used.

  Examples of the form of fibers used in the woven fabric include filament yarn, spun yarn, innovative spun yarn, and mixed composite yarn of filament yarn and spun yarn. In the spun yarn, a lot of fluff is present on the surface of the structure, and when the nonwoven fabric and the woven fabric are entangled with each other, it becomes a defect that the fluff falls off and is exposed on the surface. The filament yarn is roughly classified into a monofilament yarn composed of a single fiber and a multifilament yarn composed of a plurality of filament yarns. In the fabric used in the present invention, it is preferable to use a multifilament yarn. In monofilament yarn, the rigidity of the fiber becomes too high, and when used as artificial leather, the texture may be impaired.

  The multifilament yarn constituting the woven fabric used in the present invention preferably has a single fiber fineness of 3 dtex or less, more preferably 1.5 dtex or less, and even more preferably 1 dtex or less. If the single fiber fineness of the multifilament yarn exceeds 3 dtex, the stiffness of the fiber increases, and the texture may be impaired. The lower the single fiber fineness, the softer the texture becomes and the more suitable it can be used. However, since the single fiber is easily broken and difficult to handle, it is preferably 0.2 dtex or more.

  The total fineness of the multifilament yarn is preferably 30 dtex to 170 dtex. When a multifilament yarn having a total fineness of less than 30 dtex is used, the total fineness is preferably 30 dtex or more because the woven fiber is likely to be caught in the throat depth of the needle.

  Further, when the total fineness of the multifilament yarn exceeds 170 dtex, the basis weight of the woven fabric increases, and consequently the basis weight of the sheet-like material constituting the artificial leather increases. In addition, since the rigidity of the woven fabric is increased, it is not possible to obtain sufficient flexibility as a result of artificial leather.

  The total fineness of the multifilament yarn constituting the woven fabric is more preferably 50 dtex to 150 dtex for reasons such as rigidity and basis weight. The form of the multifilament yarn is roughly classified into false twisted multifilament yarn and raw silk without crimping, and both can be used in the present invention. When using a false twisted multifilament yarn, the multifilament yarn bulges due to crimping, and therefore tends to be easily damaged by the needle. Therefore, in the present invention, it is preferable to use raw silk.

The woven fabric used in the present invention is preferably used after being subjected to a real twist in the form of a yarn comprising the above-mentioned fibers. In this case, the number of twists is important in determining the convergence state of the fiber, and the value varies depending on the total fineness of the fiber. Therefore, the number of twists satisfying the following formula is preferably employed.
・ 1000 / (DT) <T ≦ 30000 / (DT1 / 2)
T: Actual twist number (T / m) of fibers constituting the fabric
DT: Total fineness (dtex) of the woven fabric fibers.

  When the actual number of twists is 1000 / (DT1 / 2) or less, the fiber convergence state is weak, and each single multifilament yarn is scattered, so that it is easy to hang on the needle barb and the single multifilament yarn breaks. The strength is reduced by being damaged.

  On the contrary, when the number of twists exceeds 30000 / (DT1 / 2), the dense filling structure is exceeded, so a double swirl structure is obtained. A more preferable range of the number of twists is 5000 / (DT1 / 2) ≦ T ≦ 30000 / (DT1 / 2), and a more preferable range is 12000 / (DT1 / 2) ≦ T ≦ 30000 / (DT1 / 2). is there. At this time, the actual number of twists of the warp and the weft need not be the same, but it is a preferred embodiment to have the same actual number of twists.

  When the actual number of twists of the multifilament is small, it is an effective means for suppressing damage caused by the needle to attach and bind the polymer binding agent when weaving the fabric. It can be selected from polymer binders, water-insoluble substances such as nylon, polypropylene, polyethylene, and acrylic acid esters, or pastes such as starch, PVA, and acrylic resins. In particular, it is preferable to use a water-soluble sizing agent that has a low environmental impact, and in consideration of work stability, adhesiveness, viscosity stability, and dissolution property, a sizing agent such as starch, PVA, and acrylic resin is more preferably used. Is done. The adhesion amount of the polymer binding agent is 1 to 15% by mass, and more preferably 3 to 8% by mass with respect to the mass of the fiber.

  As for the method of arranging the twisted yarns in the woven fabric when the woven fabric is constituted by twisted yarns, it is preferable that the weft yarns are constituted by alternating one S twist and one Z twist for both the warp and the weft. It is preferable that warp and warp are arranged alternately in S-twist, Z-twist, or S-twist, Z-twist. If it comprises only S piece twist or Z piece twist, a curl phenomenon will generate | occur | produce in a textile fabric and it will be easy to produce a trouble in the next process.

  In the method for producing a sheet-like material according to the present invention, among the multifilament yarns constituting the woven fabric, the inscribed circle area of a lattice composed of two arbitrary warp yarns and two weft yarns, and the needle blade used for needle punching It is particularly important to set conditions in consideration of the cross-sectional area. When the lattice area of the multifilament yarn constituting the woven fabric is large, the warp and the weft can be easily spread by the sharpness of the needle tip portion with a normal needle. In addition, even when the needle tip breaks, which occurs regularly during needle punching, it can be slid through the lattices of the multifilament yarns that make up the fabric, reducing damage to the multifilament yarns. Can be made. However, if the inscribed circle area of the lattice is small, when the needle tip portion breaks, the multifilament yarn may be damaged without sliding through the lattice of the multifilament yarn constituting the fabric. .

Therefore, in the manufacturing method of the sheet-like material of the present invention, it is necessary to satisfy the following formula.
・ 0.22 ≦ S1 / S2 ≦ 0.28
S1: Inscribed circle area of the lattice in the minimum weave pattern (mm ² )
S2: Maximum cross-sectional area (mm ² ) of the blade in contact with the fabric.

  The inscribed circle area S1 in the lattice in the minimum weave pattern referred to here means the area of the inscribed circle of the lattice woven by the warp and the weft when the fabric is observed from the surface. The value is obtained as follows. First, the fabric structure is sampled on a flat table, and the sample is arranged in such a direction as to be observed from above, and the photograph is taken about 100 times by a scanning electron microscope. Measure the diameter of the largest inscribed circle among the inscribed circles of the lattice consisting of warp and weft contained, calculate one inscribed circle area from the obtained value, and similarly for any other nine points It calculated and calculated | required and calculated the average value of a total of 10 points | pieces.

  In the present invention, for a needle used for needle punching, the blade may have a triangular or rectangular cross section, for example. When used for a normal needle punch, it is preferable to use a blade having a maximum diameter of 0.8 mm or less, but considering the case where the tip of the needle breaks and loses the sharpness of the tip during use, It is more preferable to use a blade of 0.5 mm or less that is not easily caught by the multifilaments that are formed. When the maximum diameter of the blade exceeds 0.8 mm, the opening remaining in the part through which the needle penetrates is not only a problem because it impairs the surface quality of artificial leather, but also limits the weave density in the design of the fabric. Therefore, it may happen that the strength of the woven fabric cannot satisfy the strength of the substrate for artificial leather.

  For the purpose of reducing the opening remaining in the portion through which the needle passes, the smaller the maximum diameter of the blade, the better. However, in consideration of the balance with the strength of the blade, it is most preferably 0.4 mm or more and 0.5 mm or less. It is.

  Further, in order to suppress damage to the multifilament yarn constituting the woven fabric, it is desirable to set the sum of the barb depth D and the kick-up K of the needle in the range of (D + K) <A / 2. Further, the kick-up K of the needle barb is preferably 0.03 mm or less, more preferably 0.01 mm, and still more preferably 0 mm or less. The number of barbs on the needle is preferably about 1 to 9, but more preferably 1 to 3. In the case of a needle having a plurality of barbs, if the barbs are on one ridge line of the blade, management of the direction of the needle can be facilitated.

  Next, the nonwoven fabric used by this invention is demonstrated.

  Nonwoven fabrics include those obtained by laminating short fibers such as regenerated fibers or synthetic fibers through cards, cross wrappers, random webers, and the like, and those obtained by laminating long fibers such as spunbond and meltblown. Further, these fiber layers can be preliminarily entangled with an air flow, a liquid flow, a needle punch, or the like.

  In addition, when the sheet-like material obtained by the method for producing a sheet-like material of the present invention is used for the production of artificial leather, it is particularly desirable that the fibers constituting the nonwoven fabric are ultrafine fibers or fibers that can be made ultrafine. It is an aspect. Examples of ultrafine fibers or fibers that can be made ultrafine include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyester elastomer, polyamides such as nylon 6, nylon 66, and polyamide elastomer, polyurethanes, polyolefins, and acrylonitrile. A fiber made of a polymer having a forming ability is preferred.

  Among these, fibers made of polyethylene terephthalate, polybutylene terephthalate, nylon 6, nylon 66, and the like are particularly preferably used from the viewpoint of the texture and practical performance of the processed product.

  In addition, for those that are made into ultrafine fibers by removing or exfoliating part of the polymer that constitutes the composite fiber, such as sea-island type fibers, as components to be removed, for example, polyethylene terephthalate, polystyrene, and co-polymers thereof. One or two kinds such as a polymer, polyvinyl alcohol, copolymerized polyester, and copolymerized polyamide can be used.

  The single fiber fineness of the ultrafine fibers constituting the nonwoven fabric used in the present invention is 0.05 denier to 0.8 denier in order to enhance the performance as a leather-like product, that is, flexibility, touch, appearance quality and strength properties. It is preferable that it is 0.1 denier-0.5 denier. Such an ultrafine fiber is obtained from the following ultrafine fiber generation type fiber.

  That is, as such a composite fiber, for example, a polymer array fiber composed of two or more kinds of polymers (see Japanese Patent Publication No. 44-18369) and two kinds of polymers having low compatibility are adjacent to each other. An easily split type composite fiber (see Japanese Examined Patent Publication No. 53-37456) and the like. However, the present invention is not limited to these, and a developed form of fiber can be applied based on the idea.

  Next, the relationship between the nonwoven fabric and the woven fabric in the present invention will be described.

  The mass ratio of the woven fabric to the nonwoven fabric is desirably 70% or less, and most preferably 10% to 50% by mass. This is because if the mass ratio of the woven fabric to the nonwoven fabric exceeds 70%, the fibers constituting the woven fabric are easily exposed on the surface of the nonwoven fabric. In the entanglement of the nonwoven fabric and the woven fabric, the woven fabric can be laminated on one side or both sides of the nonwoven fabric, or the fabric can be sandwiched between a plurality of nonwoven fabric webs, and the fibers can be entangled by needle punching.

  At this time, it is desirable for the nonwoven fabric to be preliminarily entangled by some means as described above in order to prevent the generation of wrinkles when the nonwoven fabric and the fabric are integrated with the needle punch. .

In that case, when a method of preliminarily entangling with a needle punch is employed, it is effective to perform the punch density at 20 / cm ² or more, preferably 100 / cm ² or more. It is preferable to give preliminary entanglement at a punch density of, more preferably to give preliminary entanglement at a punch density of 300 / cm ^{2 to} 1300 / cm ² . When the pre-entanglement is less than 20 punches / cm ^{2 as} described above, the width of the nonwoven fabric leaves room for narrowing at the time of entanglement with the woven fabric and subsequent needle punches, so the width change This is because the fabric is wrinkled and a smooth sheet cannot be obtained. Moreover, when the punch density of preliminary entanglement exceeds 1300 pieces / cm ² or more, generally the entanglement of the nonwoven fabric itself is excessively advanced, and there is a room for moving to sufficiently form the entanglement with the fibers constituting the woven fabric. This is because it is disadvantageous to realize a non-integral integrated structure in which the nonwoven fabric and the woven fabric are firmly intertwined.

In the present invention, when the woven fabric and the nonwoven fabric are entangled and integrated, the punch density range is preferably 300 / cm ^{2 to} 6000 / cm ^2, and 1000 / cm ^{2 to} 3000 / cm ^2. It is a more preferable embodiment.

  The portion of the needle punch where the needle directly acts on the woven fabric and the non-woven fabric is determined by the penetration depth of the needle. In order to firmly entangle the non-woven fabric and the woven fabric, it is necessary to make the needle deeply enter the woven fabric and the non-woven fabric. However, if the depth that the needle enters is large, the needle may break due to the impact of the needle punch, and therefore the entrance depth is preferably 1 mm to 10 mm. When the needle breaks, if the distance from the needle tip to the broken portion ≦ the penetration depth is satisfied, the needle that has lost the tip sharpness increases the possibility of damaging or breaking the multifilament constituting the fabric.

  The degree of damage of the multifilament composing the woven fabric by the needle is expressed by the tensile strength retention ratio of the woven fabric after the nonwoven fabric and the woven fabric are intertwined and integrated with each other in terms of tensile properties. The uniformity of the raised surface of the object is expressed by superiority or inferiority according to the number of multifilaments of the fabric exposed on the surface of the sheet-like object. This means that the tensile strength retention ratio can be calculated from (woven fabric tensile strength in composite sheet obtained by entanglement and integration of woven fabric and non-woven fabric) / (tensile strength of woven fabric itself). In general, it is preferable that the tensile tensile strength retention is 70% or more, and the number of multifilaments of the woven fabric exposed on the raised surface is preferably as small as possible, but the raised surface is uniform. If it is 1 place or less in the range of 20 cm × 20 cm of the sheet-like material selected arbitrarily, it is not regarded as a defect in practical use.

  Next, the ultrafine fiber-generating fiber in the obtained sheet-like material is treated with at least one component (preferably a sea component-constituting polymer) of the fiber-constituting polymer with a solubilizer or decomposition agent, or mechanically or A sheet-like material as a base for artificial leather is obtained by modification to ultrafine fibers or ultrafine fiber bundles by chemical treatment. At this time, the polymer elastic body solution is applied before and after the modification treatment of the ultrafine fiber generating fiber, and both of these orders are possible. In the case where the modification treatment is performed before the polymer elastic body solution is applied, the polymer elastic body solution is applied after applying a temporary filler capable of dissolving and removing such as polyvinyl alcohol to the nonwoven fabric so that the ultrafine fibers and the polymer elastic body do not adhere to each other. It is preferable to obtain the flexibility of the sheet, after that, and then removing the temporary filler.

  The sheet-like material as the artificial leather substrate obtained as described above can be finished into either a suede-like artificial leather or a silver-like artificial leather. When finishing a suede-like artificial leather, the artificial leather substrate is adjusted to a desired thickness by slicing or buffing, and then the artificial leather substrate is sliced or buffed by buffing with a sandpaper method or the like. After adjusting the thickness to the desired thickness by using a sandpaper or the like, the ultrafine fiber bundle on the surface of the artificial leather substrate can be raised and dyed to obtain a suede-like artificial leather. Clothing, shoes, miscellaneous goods, automobile interior materials ( It is suitably used as a car seat or a ceiling material.

[Measuring method]
(1) Area of lattice inscribed circle in minimum weaving pattern of fabric:
The fabric is sampled on a flat table, the unnatural wrinkles and tension are removed, and the sample is placed in an orientation to be observed from above. A scanning electron microscope (VE manufactured by SEM Keyence Co., Ltd.) is used. The diameter of the largest inscribed circle among the inscribed circles in the gap between the lattices woven by the warp and weft, which is included in the minimum unit of the weaving pattern randomly extracted Measurement was performed, and one area of the inscribed circle was calculated from the obtained value. The measurement and calculation were similarly performed for the other nine points, and the average value of a total of 10 points was defined as the area (mm ² ) of the lattice inscribed circle in the woven minimum pattern of the fabric.

(2) Number of napped surfaces:
The raised surface of the artificial leather dyed by five subjects was observed, and the number of multifilaments constituting the fabric exposed on the surface was measured. Observation was carried out by visually observing a randomly selected range of 20 cm × 20 cm from a distance of 20 cm to 50 cm, and when multiple multifilaments exist within 1 cm ² , they were combined and measured as one place. . These average values were calculated, and the number of raised surfaces (points / 400 cm ² ) was calculated by rounding off the second decimal place.

(3) Needle cross-sectional area:
The needle blade portion was cut with pliers in the vertical cross-sectional direction, and the cross-section was observed with a scanning electron microscope (VE-7800 manufactured by SEM Keyence) to measure the needle area. This was performed for five needles, and the average value was rounded off to the fourth decimal place. However, if a burr that can be visually confirmed remains in the cross-section cut with pliers, or if the cross-sectional shape warps, it is invalid.

[Example 1]
A fiber web is made from a raw fiber of a composite fiber made of polyethylene terephthalate as an island component and made of polystyrene as a sea component and having a mass ratio of 80/20 through a card and cross wrapping process, and then 400 pieces / a nonwoven fabric was subjected to needle punch of cm ^2.

A plain woven fabric using polyethylene terephthalate raw silk having a twist number of 2500 T / m was uniformly spread and stacked on the obtained nonwoven fabric with 84 dtex-72 filaments. The weave density of the plain weave was 37 warps / cm × 30 wefts / cm, and the area of the grid inscribed circle in the minimum weave pattern was 0.033 mm ² . In the needle punch, using a 40th needle (needle cross-sectional area 0.144 mm ² ) with a single barb with a barb depth of 0.06 mm and a kick-up of 0.03 mm and a sharp tip without breaking. 1400 pieces / cm ² from the fiber web side and 1100 pieces / cm ² from the fabric side, a total of 2500 needles / cm ² were needle punched to obtain a sheet. At this time, the area S1 of the lattice inscribed circle of the woven fabric and the cross-sectional area (S1 / S2) of the needle blade portion were 0.226. The obtained sheet was subjected to hot water shrinkage at a temperature of 98 ° C. for 3 minutes and dried at a temperature of 100 ° C. for 5 minutes. Thereafter, the above water-dispersed polyurethane liquid was applied to the sheet-like material and dried with hot air at a drying temperature of 125 ° C. for 5 minutes to obtain a sheet with polyurethane.

  The sheet with polyurethane obtained as described above is shrunk with hot water at a temperature of 98 ° C., impregnated with a 5% PVA (polyvinyl alcohol) aqueous solution, and dried with hot air at a temperature of 120 ° C. for 10 minutes. Thus, a sheet substrate having a PVA content of 6% by mass relative to the mass of the sheet with polyurethane was obtained. This sheet substrate was dipped in trichlorethylene to dissolve and remove sea components, and a seawater-removed sheet in which a nonwoven fabric made of ultrafine fibers and a woven fabric were intertwined was obtained. The seawater-free sheet comprising the nonwoven fabric and the woven fabric made of ultrafine fibers thus obtained is immersed in a DMF (dimethylformamide) solution of polyurethane adjusted to a solid content concentration of 12%, and then in an aqueous solution having a DMF concentration of 30%. To solidify the polyurethane. Thereafter, PVA and DMF are removed with hot water and dried with hot air at a temperature of 110 ° C. for 10 minutes, whereby an artificial leather having a polyurethane mass of 27 mass% with respect to the total mass of the ultrafine fibers made of island components and the fabric is obtained. Obtained. Thereafter, the half-cut in the thickness direction was performed by a half-cut having an endless band knife, and the half-cut surface was ground using a JIS # 240 sandpaper in three stages to form napped hairs to produce artificial leather.

Furthermore, it dye | stained with the disperse dye using the circular dryer, and obtained artificial leather. The number of raised surfaces of the obtained artificial leather was 0.0 point / 400 cm ^2, which was excellent in uniformity of the raised surfaces, and was dense and of good quality. The results are shown in Table 1.

[Example 2]
Use a 40% needle with a single barb broken at 4mm from the tip at a rate of 0.002%. The other needles have a single barb with a barb depth of 0.06mm and a kick-up of 0.03mm. Processing was carried out in the same manner as in Example 1 except that a sharp 40th needle (needle cross-sectional area 0.144 mm ² ) was used without breaking, and an artificial leather was produced. The number of raised surfaces of the obtained artificial leather was 0.8 / 400 cm ² , and although the multifilaments could be confirmed slightly on the raised surfaces, the quality was good. The results are shown in Table 1.

[Example 3]
For the needle punch, except for using a 42nd needle (needle cross-sectional area 0.130 mm ² ) with a single barb with a barb depth of 0.06 mm, a kick-up of 0.03 mm, and a sharp tip without breaking. Were processed in the same manner as in Example 1 to produce artificial leather. The number of raised surfaces of the obtained artificial leather was 0.0 points / 400 cm ^2, and the uniformity of the raised surfaces was excellent. The results are shown in Table 1.

[Example 4]
A single barb 42nd needle with a broken portion from the tip to 4mm is used at a rate of 0.002%. The other needles have a single barb with a barb depth of 0.06mm and a kick-up of 0.03mm. Was processed in the same manner as in Example 1 except that a sharp 42-th needle (needle cross-sectional area 0.130 mm ² ) was used without breaking, and an artificial leather was produced. The number of raised surfaces of the obtained artificial leather was 0.0 points / 400 cm ^2, and the uniformity of the raised surfaces was excellent. The results are shown in Table 1.

[Example 5]
For the needle punch, except for using a 43rd needle (needle cross-sectional area 0.115 mm ² ) with a single barb with a barb depth of 0.06 mm, a kick-up of 0.03 mm, and a sharp tip without breaking. Were processed in the same manner as in Example 1 to produce artificial leather. The number of raised surfaces of the obtained artificial leather was 0.0 points / 400 cm ^2, and the uniformity of the raised surfaces was excellent. The results are shown in Table 1.

[Example 6]
A raw fiber of a composite fiber composed of polyethylene terephthalate as an island component and PET (copolymerized PET) copolymerized with 8 mol% of sodium 5-sulfoisophthalate as a sea component is 80/20. A fiber web was prepared through a cross wrapping process, and then a raw cotton using was produced.

  The nonwoven fabric obtained using the above raw cotton was subjected to hot water shrinkage treatment at a temperature of 98 ° C. for 3 minutes and dried at a temperature of 100 ° C. for 5 minutes. Thereafter, a water-dispersed polyurethane liquid was applied, and hot-air drying was performed at a drying temperature of 125 ° C. for 5 minutes to obtain a polyurethane-attached sheet having a polyurethane adhesion amount of 35% by mass with respect to the island component of the nonwoven fabric.

The polyurethane-coated sheet obtained as described above was immersed in a 2% aqueous sodium hydroxide solution heated to a temperature of 90 ° C. and treated for 30 minutes to dissolve and remove the sea component polymer from the composite fiber. Others were processed in the same manner as in Example 1. The number of raised surfaces of the obtained artificial leather was 0.0 points / 400 cm ² , excellent in uniformity of the raised surfaces, and the texture was soft. The results are shown in Table 1.

[Example 7]
Use a 40% needle with a single barb broken at 4mm from the tip at a rate of 0.002%. The other needles have a single barb with a barb depth of 0.06mm and a kick-up of 0.03mm. Processing was carried out in the same manner as in Example 7 except that a sharp 40th needle (needle cross-sectional area 0.130 mm ² ) was used without breaking, and an artificial leather was produced. The number of raised surfaces of the obtained artificial leather was 0.8 points / 400 cm ² , which was excellent in the uniformity of the raised surfaces. The results are shown in Table 1.

[Comparative Example 1]
The needle punching was carried out except that a single barb with a barb depth of 0.06 mm and a kick-up of 0.03 mm was used, and a sharp 38th needle (needle cross-sectional area 0.159 mm ² ) was used without breaking the tip. Processing was carried out in the same manner as in Example 1 to produce artificial leather. The number of raised surfaces of the obtained artificial leather was 2.1 points / 400 cm ² , and the multifilament was exposed on the raised surfaces, and the surface quality was poor. The results are shown in Table 1.

[Comparative Example 2]
Use a single barb 38th needle with a portion of 4mm from the tip broken at a rate of 0.002%, and the other needles have a 38th single barb with 0.06mm barb depth and 0.03mm kickup, Processing was carried out in the same manner as in Example 1 except that a needle having a pointed shape without breaking the tip (needle cross-sectional area 0.159 mm ² ) was used to produce an artificial leather. The number of raised surfaces of the obtained artificial leather was 4.4 points / 400 cm ² , and multifilaments were exposed at a plurality of locations on the raised surface, resulting in poor surface uniformity. The results are shown in Table 1.

  In the table, in the column of whether or not the tip of the needle is broken, the case where a needle having a broken part up to 4 mm from the tip is used is indicated by ◯, and the case where it is not used is indicated by no.

Claims (5)

A sheet-like material characterized in that the number of yarns constituting the fabric exposed on the surface is intertwined with the ultrafine fibers and 1/400 cm ² or less.   The sheet-like object according to claim 1, which has a raised surface formed by raising.   The sheet-like material according to claim 1 or 2, which is impregnated with a polymer elastic body. In the manufacturing process of the sheet-like material which makes an ultrafine fiber and a textile fabric entangle with a needle punch, needle punching is carried out on the conditions which satisfy | fill the following formula.
・ 0.22 ≦ S1 / S2 ≦ 0.28
S1: Maximum inscribed circle area in the lattice in the minimum weave pattern (mm ² )
S2: Maximum cross-sectional area of the needle blade portion in contact with the fabric (mm ² )   The method for producing a sheet-like product according to claim 4, further comprising a napped surface formed on the surface.